Mvc.Api.Analyzers.ApiConventionAnalyzer throws ArgumentNullException when action doesn't return

[Briaoeuidhtns]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

If an action just has a throw expression and no return, the analyzer throws a NullArgumentException with no other information or location in the code.

Expected Behavior

No exception is thrown, or a proper warning about never returning is given

Steps To Reproduce

https://github.com/Briaoeuidhtns/Mvc.Api.Analyzers.ApiConventionAnalyzer-NullArgumentException-on-no-return-repro

Exceptions (if any)

CSC : warning AD0001: Analyzer 'Microsoft.AspNetCore.Mvc.Api.Analyzers.ApiConventionAnalyzer' threw an exception of type 'System.ArgumentNullException' with message 'Value cannot be null. (Parameter 'target')'.

.NET Version

7.0.302

Anything else?

No response

[captainsafia]

@Briaoeuidhtns Thanks for reporting this issue!

So, this bug is a result of some buggy code in our analyzer. We enter the problematic code path when we try to resolve the response types associated with an action method here:

aspnetcore/src/Mvc/Mvc.Api.Analyzers/src/ApiConventionAnalyzer.cs

Line 48 in be14dda

var hasUnreadableStatusCodes = !ActualApiResponseMetadataFactory.TryGetActualResponseMetadata(symbolCache, (IMethodBodyOperation)context.Operation, out var actualResponseMetadata);

Which evaluates to a null return value here:

aspnetcore/src/Mvc/Mvc.Api.Analyzers/src/ActualApiResponseMetadataFactory.cs

Line 75 in be14dda

var statementReturnType = returnedValue.Type;

We'll probably want to add guards to this particularly codepath. One thing to note here is that we ship these analyzers in the SDK, so users would have to pull in a new SDK version in order to approach the fix.

@Briaoeuidhtns Are you interested in contributing a PR for this bug?

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[Briaoeuidhtns]

Thanks for the direction. Yes, I'll look into getting a PR together to address this.

[captainsafia]

Thanks for the direction. Yes, I'll look into getting a PR together to address this.

Great! Another pointer: this is the test file you'll want to use for this.